Tony, A moving fluid has a lower pressure due to the Bernoulli effect. This principle explains the operation of aspirators and the lift of airplanes. An example of this (I understand) is that if you blow through the hole in the center of a spool then a piece of paper placed at the end of the spool will be attracted to it. I suspect that this is what you are experiencing.
Gordon At 01:12 AM 7/14/99 , Tony Moss wrote: >Fellow shadow watchers, > No doubt the following is well known but it came >as a surprise to me. >While filling a watering can with a garden hosepipe adjusted to give a >powerful single jet* I have to PUSH the hose firmly into the can to >overcome the reaction from the water jet BUT as soon as I dip the nozzle >into the water a smaller force takes over and seems to PULL it gently >down into the water. (no measurements made so purely subjective >conclusions) > >i.e. the force reverses on entry! > >Why is this so? and, if I'm right, how do 'jet' boats, working on the >reaction principle, function at all I wonder? > >* The nozzle is one of those variable things which screw back and forth >around a central pin. The 'single jet' is more of a tight spray pattern >really. > >Tony (should have paid more attention in Physics lessons) Moss Gordon Uber [EMAIL PROTECTED] Reynen & Uber Web Design http://www.ubr.com/rey&ubr/ Webmaster: Clocks and Time http://www.ubr.com/clocks/
